Sunday, June 27, 2010

operating systems

source: http://en.wikipedia.org/wiki/List_of_operating_systems


Operating system

General
History · Timeline · List · Comparison · Usage share · Development · Advocacy


Kernel
Architectures
General
Subtypes
Components


Process management

Memory management

Examples
UNIX · OpenSolaris · GNU · Linux · BSD · Windows · Mac OS X · AmigaOS · MorphOS · BeOS · IBM OS/2 · ReactOS · MS-DOS · more…


Miscellaneous concepts




Google

  • Google Chrome OS is an upcoming open source operating system designed to work exclusively with web applications. Announced on July 7, 2009, Chrome OS is set to have a publicly available stable release during the second half of 2010. 


IBM

  • OS/360 and successors on IBM mainframes
    • OS/360 (First official OS targeted for the System/360 architecture, saw customer installations of the following variations:)
      • PCP (Primary Control Program, a kernel and a ground breaking automatic space allocating file system)
      • MFT (original Multi-programming with a Fixed number of Tasks, replaced by MFT II.
      • MFT II (Multi-Programming with a Fixed number of Tasks, had up to 15 fixed size application partitions, plus partitions for system tasks, initially defined at boot time but redefinable by operator command).
      • MVT (Multi-Programming Variable Tasks, had up to 15 application regions defined dynamically, plus additional regions for system tasks)
    • OS/VS (The official port of OS/360 targeted for the System/370 virtual memory architecture. "OS/370" is not correct name for OS/VS1 and OS/VS2, but rather refers to OS/VS2 MVS and MVS/SP Version 1. Customer installations in the following variations:)
      • SVS (Single Virtual Storage (both VS1 & VS2 began as SVS systems))
      • OS/VS1 (Operating System/Virtual Storage 1, Virtual-memory version of MFT II)
      • OS/VS2 (Operating System/Virtual Storage 2, Virtual-memory version of OS/MVT) but without multiprocessing support.
    • MVS/SE (MVS System Extensions)
    • MVS/SP (MVS System Product)
    • MVS/XA (MVS/SP V2. MVS supported eXtended Architecture, 31bit addressing)
    • MVS/ESA (MVS supported Enterprise System Architecture, horizontal addressing extensions: data only address spaces called Dataspaces); a Unix environment was available starting with MVS/ESA V4R3.
    • OS/390 (Upgrade from MVS, with an additional Unix environment.)
    • z/OS (OS/390 supported z/Architecture, 64bit addressing.)
  • DOS/360 and successors on IBM mainframes
    • BOS/360 (Early interim version of DOS/360, briefly available at a few Alpha & Beta System 360 sites)
    • TOS/360 (Similar to BOS above and more fleeting, able to boot and run from 2x00 series tape drives)
    • DOS/360 (Disk Operating System (DOS). First commonly available OS for System/360 due to problems in the OS/360 Project. Multi-programming system with up to 3 partitions.)
      • DOS/360/RJE (DOS/360 with a control program extension that provided for the monitoring of remote job entry hardware (card reader & printer) connected by dedicated phone lines.)
    • DOS/VS (First DOS offered on System/370 systems, provided virtual storage.)
    • DOS/VSE (upgrade of DOS/VS. Still had fixed size processing partitions, but up to 14 partitions.) Also referred to as VSE.
    • VSE/SP Program product replacing DOS/VSE and VSE/AF.
    • VSE/ESA (DOS/VSE extended virtual memory support to 32 bit addresses (Extended System Architecture)).
    • z/VSE (Latest version of the four decades old DOS lineage. Now supports 64 bit addresses, multiprocessing, multiprogramming, SNA, TCP/IP, and some virtual machine features in support of Linux workloads. (All DOS ref. IBM website))
  • TPF Line on IBM mainframes (real-time operating system, largely used by airlines)
  • Others on IBM mainframes
    • IBSYS (tape based operating system for IBM 7090 and IBM 7094)
    • CTSS (The Compatible Time-Sharing System developed at MIT's Computation Center)
    • RTOS/360 (Real Time Operating System, run on 5 NASA custom System/360/75s. A mash up by the Federal Systems Division of the MFT system management, PCP basic kernel and file system, with MVT task management and FSD custom real time kernel extensions and error management. The pinnacle of OS/360 development .)
    • MTS (Michigan Terminal System for IBM System/360)
    • TSS/360 (Time Sharing System for IBM System/360)
    • MUSIC/SP (developed by McGill University for IBM System/370)
    • IJMON (A bootable serial I/O monitor for loading programs for IBM 1400 and IBM 1800.)
  • IBM 8100
    • DPCX (Distributed Processing Control eXecutive)
    • DPPX (Distributed Processing Programming Executive)
  • IBM PC and successors on x86 architecture
    • PC DOS / IBM DOS
      • PC DOS 1.x, 2.x, 3.x (developed jointly with Microsoft)
      • IBM DOS 4.x, 5.0 (developed jointly with Microsoft)
      • PC DOS 6.x, 7, 2000
    • OS/2
      • OS/2 1.x (developed jointly with Microsoft)
      • OS/2 2.x
      • OS/2 Warp 3
      • OS/2 Warp 4
      • eComStation (Warp 4.5/Workspace on Demand, rebundled by Serenity Systems International)


Apple Inc.

For Apple II
For Apple III
  • SOS (Sophisticated Operating System)
For Apple Lisa
  • Lisa OS
For Apple Newton
Classic Mac OS
Unix-like operating systems

Unix-like

[edit] Research Unix-like and other POSIX-compliant

[edit] Free/Open source Unix-like

  • BSD (Berkeley Software Distribution, a variant of Unix for DEC VAX hardware)
    • FreeBSD (one of the outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
    • NetBSD (one of the outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
  • GNU
  • μnix (concept unix-like operating system for ATMEL microcontrollers)
  • Linux (GNU Free/Open Source Operating System Software combined with the Linux kernel)
See also: List of Linux distributions

 Other Unix-like

  • TUNIS (University of Toronto) 

Disk Operating Systems

Main article: DOS

Digital Research Inc

Posted by at No comments:
Labels:

Friday, June 25, 2010

Google

source: http://en.wikipedia.org/wiki/Google

Google Inc. (NASDAQ: GOOG, FWB: GGQ1) is a multinational public cloud computing, Internet search, and advertising technologies corporation.

Google hosts and develops Internet-based services and products,[5] and generates profit primarily from advertising through its AdWords program.

The company's stated mission from the outset was "to organize the world's information and make it universally accessible and useful",[11] and the company's unofficial slogan – coined by Google engineer Paul Buchheit – is Don't be evil.   anti-corporate, no evil philosophy

company's core search engine. The Google web search engine is the company's most popular service.

users can search for the information they desire, through the use of keywords and operators.

spread to specific services , including an image search engine, the Google News search site

Google Maps

Google Video, which allowed users to upload, search, and watch videos from the Internet.[97] In 2009, however, uploads to Google Video were discontinued.[98] 

Google Books. The company began scanning books and uploading limited previews, and full books where allowed, into their new book search engine. However, a number of copyright disputes arose, and Google reached a revised settlement in 2009 to limit its scans to books from the U.S., the U.K., Australia and Canada.[99]

Google Desktop, a desktop search application used to search for files local to one's computer.


The company offers online productivity software, such as its Gmail e-mail software, and social networking tools, including Orkut and, more recently, Google Buzz. Google's products extend to the desktop as well, with applications such as the web browser Google Chrome, the Picasa photo organization and editing software, and the Google Talk instant messaging application.



Google Docs, another part of Google's productivity suite, allows users to create, edit, and collaborate on documents in an online environment, spreadsheet editing program, and program to edit presentations.

Google Translate is a server-side machine translation service, which can translate between 35 different languages.  The software uses corpus linguistics techniques, where the program "learns" from professionally translated documents, specifically United Nationsand European Parliament proceedings.[118] Furthermore, a "suggest a better translation" feature accompanies the translated text, allowing users to indicate where the current translation is incorrect or otherwise inferior to another translation.

Google News

The site Google News Report monitors the Google News homepage, and for May 2007, published this list of the top 26 sites most-often referenced by Google News.
Rank News Source
1 The New York Times
2 Washington Post
3 Houston Chronicle
4 Bloomberg L.P.
5 Los Angeles Times
6 Reuters
7 Forbes
8 Monsters and Critics.com
9 guardian.co.uk
10 Voice of America
11 International Herald Tribune
12 Boston Globe
13 Chicago Tribune
14 BBC News
15 San Francisco Chronicle
16 CBS News
17 Times Online
18 Xinhua
19 Wall Street Journal
20 USA Today
21 Fox News
22 CNN
23 Seattle Post Intelligencer
24 MSNBC
25 ABC News
25 Daily Mail and Mail On Sunday
26 The Times of India








Google Chrome, an open-source web browser

Google Chrome OS, an open-source Linux-based operating system that includes only a web browser and is designed to log users into their Google account,

Google Wave was described as a product that helps users communicate and collaborate on the web. The service is Google's "email redesigned", with realtime editing, the ability to embed audio, video, and other media, and extensions that further enhance the communication experience.



Google leads the development of the Android mobile phone operating system, used on a number of phones such as the Nexus One and Motorola Droid.

Because of its popularity and numerous products,

  Alexa lists Google as the Internet's most visited website.[19]

Google is also Fortune Magazine's fourth best place to work,[20] and

  BrandZ's most powerful brand in the world.[21]

The dominant market position of Google's services has led to criticism of the company over issues including privacy, copyright, and censorship.[22][23]


Google runs over one million servers in data centers around the world,[14] and processes over one billion search requests[15] and twenty petabytes of user-generated data every day




PageRank, where a website's relevance was determined by the number of pages, and the importance of those pages, that linked back to the original site


Google began selling advertisements associated with search keywords. 


Keywords were sold based on a combination of price bids and clickthroughs, with bidding starting at five cents per click.


Using technology from the company DoubleClick, Google can determine user interests and target advertisements appropriately so they are relevant to the context they are in and the user that is viewing them.


Google Analytics allows website owners to track where and how people use their website, allowing for in-depth research into getting users to go where you want them to go.[91]


Google's AdWords allows advertisers to display their advertisements in the Google content network, through either a cost-per-click or cost-per-view scheme.


Google AdSense, allows website owners to display these advertisements on their website, and earn money every time ads are clicked.











Industry Internet, Computer software



Subsidiaries YouTube, DoubleClick, On2 Technologies, GrandCentral, Picnik, Aardvark, AdMob

Website Google.com



Google Earth gave a 3-D view of the Earth.

DoubleClick  giving Google valuable relationships  Web publishers and advertising agencies.[63

2005
In 2005, Google partnered with NASA Ames Research Center to build 1,000,000 square feet (93,000 m2) of offices.[68] The offices would be used for research projects involving large-scale data management, nanotechnology, distributed computing, and the entrepreneurial space industry.

Google entered into a partnership with Sun Microsystems in October 2005 to help share and distribute each other's technologies.[69
partnered with AOL of Time Warner,[70] to enhance each other's video search services

financing the new .mobi top-level domain for mobile devices, along with other companies including Microsoft, Nokia, and Ericsson.

launch "Adsense for Mobile", taking advantage of the emerging mobile advertising market.[72] 

Google and Fox Interactive Media of News Corp. entered into a  agreement to provide search and advertising on popular social networking site MySpace.

2006

acquired the video-sharing site YouTube

2008

partnership with GeoEye and launched a satellite providing Google with high-resolution (0.41 m monochrome, 1.65 m color) imagery for Google Earth

hosting an archive of Life Magazine's photographs

2010

Google purchased Global IP Solutions, a Norway based company that provides web-based teleconferencing and other related services. This acquisition will enable Google to add telephone-style services

acquisition of the mobile ad network, AdMob
Posted by at No comments:
Labels:

Wednesday, June 23, 2010

performance of computer system


"How well is the computer doing the work it is supposed to do?"[2]
Computer performance is characterized by the amount of useful work accomplished by a computer system compared to the time and resources used.
Depending on the context, good computer performance may involve one or more of the following:



Computer performance metrics include availability, response time, channel capacity, latency, completion time, service time, bandwidth, throughput, relative efficiency, scalability,performance per watt, compression ratio, Instruction path length and speed up. CPU benchmarks are available.[1]


Computer software performance, particularly software application response time, is an aspect of software quality that is important in human–computer interactions.



The performance of any computer system can be evaluated in measurable, technical terms, using one or more of the metrics listed above. This way the performance can be
- compared relative to other systems or the same system before/after changes

Technical performance metrics

There is a wide variety of technical performance metrics that indirectly affect overall computer performance.
Because there are too many programs to test a CPU's speed on all of them, benchmarks were developed. The most famous benchmarks are the SPECint and SPECfp benchmarks developed by Standard Performance Evaluation Corporation and the ConsumerMark benchmark developed by the Embedded Microprocessor Benchmark Consortium EEMBC.
Some important measurements include:
  • Instructions per second – Most consumers pick a computer architecture (normally Intel IA32 architecture) to be able to run a large base of pre-existing, pre-compiled software. Being relatively uninformed on computer benchmarks, some of them pick a particular CPU based on operating frequency (see megahertz myth).
  • FLOPS – The number of floating-point operations per second is often important in selecting computers for scientific computations.
  • Performance per watt – System designers building parallel computers, such as Google, pick CPUs based on their speed per watt of power, because the cost of powering the CPU outweighs the cost of the CPU itself. [1][2]
  • Some system designers building parallel computers pick CPUs based on the speed per dollar.
  • System designers building real-time computing systems want to guarantee worst-case response. That is easier to do when the CPU has low interrupt latency and when it has deterministic response. (DSP[disambiguation needed][clarification needed])
  • Computer programmers who program directly in assembly language want a CPU to support a full-featured instruction set.
  • Low power – For systems with limited power sources (e.g. solar, batteries, human power).
  • Small size or low weight - for portable embedded systems, systems for spacecraft.
  • Environmental impact – Minimizing environmental impact of computers during manufacturing and recycling as well as during use. Reducing waste, reducing hazardous materials. (seeGreen computing).





While clock rates are a valid way of comparing the performance of different speeds of the same model and type of processor, other factors such as pipeline depth and instruction sets can greatly affect the performance when considering different processors.


CPUs with many execution units often complete real-world and benchmark tasks in less time than the supposedly faster high-clock-rate CPU.


 If performance is critical, the only benchmark that matters is the target environment's application suite.


Users can have very different perceptions of performance than benchmarks may suggest. In particular, users appreciate predictability — servers that always meet or exceed service level agreements. Benchmarks tend to emphasize mean scores (IT perspective) rather than low standard deviations (user perspective).






source: http://en.wikipedia.org/wiki/Benchmark_(computing), http://en.wikipedia.org/wiki/Computer_performance,
Posted by at No comments:
Labels:
Subscribe to: Posts (Atom)